scholarly journals The megalopa and early juvenile development of Hepatus pudibundus (Crustacea: Brachyura: Aethroidea) reared from neuston samples

2008 ◽  
Vol 25 (4) ◽  
pp. 608-616 ◽  
Author(s):  
Maria L. Negreiros-Fransozo ◽  
Adilson Fransozo ◽  
Gustavo L. Hirose
Keyword(s):  
Intraspecific Variation ◽  
Shallow Waters ◽  
Larval Morphology ◽  
Western Atlantic ◽  
Laboratory Rearing ◽  
Early Juvenile ◽  
Levels Of Detail ◽  
Juvenile Stages ◽  
Juvenile Crab ◽  
Juvenile Development

Hepatus pudibundus (Herbst, 1785) is a crab commonly found in shallow waters of the Western Atlantic. Its larval and early post-larval morphology have already been described from laboratory hatched material. Around 200 megalopae of H. pudibundus were collected in neuston samples from the Ubatuba region, Brazil, during the summer of 2005-2006 and were successfully reared under laboratory conditions. The size of the megalopae obtained in the neuston was similar to those specimens previously described in the literature, except that the juvenile crab stages reared in the laboratory were slightly larger, probably due to the better feeding conditions in the laboratory. The duration of the juvenile stages was shorter in the present study than in previous attempts at laboratory rearing, even if conditions appeared to be similar. The main differences observed between studies were in megalopal morphology, which may be attributable to intraspecific variation but, possibly, also due to differences in levels of detail than previously performed.

scholarly journals Decapodid and early juvenile development in the protandrous shrimp Campylonotus vagans (Crustacea: Decapoda: Caridea), with notes on larval morphology

2003 ◽  
Vol 83 (1) ◽  
pp. 103-109 ◽  
Author(s):  
Sven Thatje ◽  
Gustavo A. Lovrich
Keyword(s):  
Low Temperatures ◽  
Juvenile Stage ◽  
Tierra Del Fuego ◽  
Caridean Shrimp ◽  
Early Juvenile ◽  
Morphological Variations ◽  
Sexual Determination ◽  
Juvenile Stages ◽  
Two Stages ◽  
Juvenile Development

The decapodid and first two juvenile stages of the caridean shrimp Campylonotus vagans from the Subantarctic Beagle Channel (Tierra del Fuego, Argentina) are described and illustrated in detail. The complete larval and early juvenile development of this species from rearings under controlled laboratory conditions were analysed. Zoeal morphology in two stages of an abbreviated development was identical to a description from plankton and hatched larvae of a previous work, and therefore we only compare and discuss slight morphological variations in this study. The first juvenile is large and already resembles some features of adults, lacking all ventral rostral and the fourth dorsal rostral spine only which appears in the following stage, and the second pereiopod not yet being as predominant as in adults. Sexual determination is not yet possible up to the described second juvenile stage. The abbreviated larval development in a Subantarctic shrimp species is discussed as an adaptation to low temperatures and pronounced seasonality.

Delayed determination of claw laterality in lobsters loss of target

Development ◽  
1989 ◽  
Vol 107 (3) ◽  
pp. 547-551
Author(s):  
C.K. Govind ◽  
J. Pearce
Keyword(s):  
Critical Period ◽  
Early Juvenile ◽  
Juvenile Stages ◽  
Juvenile Development

Lateralization of the paired claws into a major crusher minor cutter type is determined during the 4th and 5th juvenile development of the lobster, Homarus claws during this critical period delays the laterality until the 6th stage when regenerate claws Continued loss into the 6th stage, and beyond, laterality, resulting in lobsters with paired cutter critical period for determining claw laterality may extended for a brief time to cater for claw loss, common in these early juvenile stages.

scholarly journals Scolex development, morphology and mode of attachment of Wenyonia virilis Woodland, 1923 (Cestoidea, Caryophyllidea)

2006 ◽  
Vol 51 (1) ◽  
Author(s):  
Mohammed Ibraheem ◽  
John Mackiewicz
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Host Tissue ◽  
Central Group ◽  
Early Juvenile ◽  
Juvenile Stages ◽  
Mode Of Attachment ◽  
Terminal Structure ◽  
Juvenile Development ◽  
Scanning Electron

AbstractDevelopment and morphology of the scolex and mode of attachment of Wenyonia virilis Woodland, 1923, a caryophyllaeid cestode from the silurid Nile fish Synodontis schall (Bloch et Schneider, 1801), were studied by means of light and scanning electron microscopy (SEM). Scolex and genital primordia changes through four stages of juvenile development are described. Longitudinal ridges do not appear on the scolex until the cestode has well defined genital primordia. This is in stark contrast to other caryophyllidean genera in which the basic morphology of the adult scolex becomes evident at the procercoid stage in the oligochaete intermediate host. The scolex of the adult has 13 to 19 prominent longitudinal ridges and deep furrows that come together at the apex to form an apical ring, a protrusible terminal introvert within the apical ring that forms a deep apical pouch when fully retracted, and a central group of Faserzellen. The scolex of W. virilis appears similar to the rugomonobothriate scolex of another African caryophyllid, Monobothrioides chalmersius (Woodland, 1924). Comparisons are made with other caryophyllideans having a scolex with a terminal structure: Monobothrium Diesing, 1863, Djombangia Bovien, 1926 and Caryoaustralus Mackiewicz et Blair, 1980. The terminal introvert may be responsible for attachment in early juvenile stages, but may be supplemented by the longitudinal ridges and furrows later in development. Host tissue appears to be drawn into these furrows that function as weak organs of attachment. We could not determine how the introvert of adult worms functions in attachment. At the site of attachment, the mucosa showed necrosis and degeneration and the submucosa exhibited vacuolization and infiltration with lymphocytes and leucocytes.

scholarly journals Intertidal habitat use of bottlenose dolphins (Tursiops truncatus) in Bahía San Antonio, Argentina

2017 ◽  
Vol 98 (5) ◽  
pp. 1109-1118
Author(s):  
Els Vermeulen
Keyword(s):  
Habitat Use ◽  
Intertidal Zone ◽  
Tursiops Truncatus ◽  
San Antonio ◽  
Bottlenose Dolphins ◽  
High Tide ◽  
Marine Conservation ◽  
Shallow Waters ◽  
Encounter Rate ◽  
Western Atlantic

Very little information is available on bottlenose dolphin (Tursiops truncatus) habitat use in the South-western Atlantic. It is, however, essential in understanding their ecology and to improve conservation management. In this study, habitat use of bottlenose dolphins was examined in Bahía San Antonio, an area frequented by the species. Given the large tidal amplitude and extended intertidal zone in this bay, special focus was given to the intertidal vs subtidal habitat use patterns. Bottlenose dolphins were observed in only half of the surveyed area, with on average 1 dolphin group encountered per 100 km surveyed. All dolphin groups were seen in shallow waters <10 m deep. GLM analyses showed that especially during high tide, depth had an important effect on the dolphin encounter rate, with most dolphin groups encountered in the intertidal zone. While in the intertidal zone, most dolphin groups were observed to be engaged in surface feeding activities. The presented data indicate dolphins remained in shallow waters, and moved to the intertidal zone during high tide where they appear to find feeding opportunities. This information is believed to be of high value in understanding this population's ecological needs, and essential when aiming to improve marine conservation efforts at times of increased anthropogenic pressures in the area.

A new species of Placospongia Gray, 1867 (Porifera, Demospongiae, Placospongiidae) and new record of P. ruetzleri van Soest, 2017 from Northeast, Brazil

Zootaxa ◽  
2021 ◽  
Vol 5072 (1) ◽  
pp. 12-22
Author(s):  
ROSA MÁCOLA ◽  
CARLA MENEGOLA
Keyword(s):  
New Species ◽  
New Record ◽  
Identification Key ◽  
Type Locality ◽  
Shallow Waters ◽  
Northeast Brazil ◽  
Western Atlantic ◽  
First Time ◽  
A New Species

A new species of Placospongia is described from Bahia State, Brazil. Placospongia giseleae sp. nov.. The specimen is found on the underside of rocks in shallow waters (0-20m), and is unique by having a spiculation consisting of two tylostyle categories, selenasters and acanthomicrorhabds. In addition, Placospongia ruetzleri, is recorded for the first time to Bahia state, 2.974 km southwards from its type locality, the Guyana shelf. The diversity of Placospongia species is raised from two to four taxa. An identification key for Western Atlantic Placospongia species is presented.  

scholarly journals The Most Extreme Sexual Size Dimorphism among Birds: Allometry, Selection, and Early Juvenile Development in the Great Bustard (Otis tarda)

The Auk ◽  
2009 ◽  
Vol 126 (3) ◽  
pp. 657-665 ◽  
Author(s):  
Juan C. Alonso ◽  
Marina Magaña ◽  
Javier A. Alonso ◽  
Carlos Palacín ◽  
Carlos A. Martín ◽  
...  
Keyword(s):  
Sexual Size Dimorphism ◽  
Great Bustard ◽  
Size Dimorphism ◽  
Otis Tarda ◽  
Early Juvenile ◽  
Juvenile Development

scholarly journals Morphology of juvenile phase of Achelous spinimanus (Latreille, 1819) (Crustacea, Decapoda, Portunidae) reared in laboratory

2015 ◽  
pp. 1-17
Author(s):  
Eduardo Antonio Bolla Júnior ◽  
Maria Lucia Negreiros Fransozo
Keyword(s):  
Sexual Differentiation ◽  
Morphological Characters ◽  
Juvenile Stage ◽  
Western Atlantic ◽  
Juvenile Phase ◽  
The Third ◽  
Third Stage ◽  
Natural Photoperiod ◽  
Number Of Segments ◽  
Juvenile Development

The swimming crabAchelous spinimanusis an important fishery component of several countries in the Western Atlantic; therefore, knowledge of the different phases of its life cycle is essential for good management of this resource. The juvenile development ofA. spinimanuswas investigated in the laboratory, from megalopae captured in neuston samples at Ubatuba, São Paulo, Brazil (23°26′S 46°09′W), during the summer months of 2005–2007. Rearing was performed in a constant temperature (25 ± 1°C), filtered seawater from the collection location (35 psu) and natural photoperiod. We obtained nine stages of the juvenile phase. All the morphological characters that allow the recognition of the first juvenile stage were drawn and described, as well as the main alterations that occur in the following stages. The sexual differentiation based on the number of pleopods becomes apparent from the third stage on. Some important characters in the identification of the species at the juvenile phase are the number of segments on the exopod of antennule, on the antennal flagellum and on the palp of mandible, beyond the absence of pleopods (even rudimentary) in the first stage.

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